JPH02130085A - Transmitting system for television signal - Google Patents

Abstract

PURPOSE:To transmit a wide band video signal at a 4.2MHz band while keeping the compatibility with an NTSC signal by forming a transmitting signal having the compatibility with the NTSC signal for the high area component area of a luminance signal with the frequency shifting of plural carriers, and transmitting the wide band video signal through the NTSC transmission line. CONSTITUTION:By shifting the frequency of plural carriers, the transmitting signal having the compatibility with an NTSC signal for the high area component area of a luminance signal is formed, and while the compatibility with the NTSC signal is kept, a wide band video signal is transmitted through an NTSC transmission line. Thus, while the compatibility with the NTSC signal is kept, the high area information of a luminance signal can be increased drastically (about two times). Consequently, at the NTSC signal used for the broadcasting and the like conventionally, the defect that the horizontal high area information is reduced compared with vertical information is removed, and the result can be applied even to the transmission of a high resolution signal such as high-vision and EDTV.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal transmission system for a high-definition television system that is compatible with the current NTSC system.

More specifically, the present invention uses band compression technology to
This relates to a method for transmitting high-definition images.

[Summary of the Invention] The present invention relates to a transmission method for wideband video signals such as high-definition, and enables narrowband transmission of wideband signals while maintaining compatibility with NTSC signals using a multi-frequency interleaving method. be.

[Prior Art] As is well known, the luminance signal band of the NTSC signal is 4.2 MHz, the bands of I and Q signals, which are color difference signals, are 1.5 MIIz and 0.5 MHz, respectively, and the aspect ratio is 4:3. It becomes.

The luminance signal and the color difference signal are frequency multiplexed by frequency interleaving, and if a frame memory is used, the luminance signal and the color difference signal can be completely separated for an image in a still image area.

Further, discrimination between a moving image area and a still image area is performed by performing motion detection from a low-frequency 2Mtlz signal, and in the moving image area, a luminance signal and a color difference signal are separated using a line memory.

[Problem to be solved by the invention] However, the band of the luminance signal and two color difference signals that can be transmitted by Nrsc (No. 3) is narrower than that of high-definition. Also, the aspect ratio is 4=3, Unlike 16=9 in high-definition, it cannot be used as is for transmitting wideband signals such as high-definition.

Therefore, it is an object of the present invention to provide a transmission system that makes it possible to transmit wideband video signals in a 4.2 MHz band while maintaining compatibility with NTSC signals.

[Means for Solving the Problems] The transmission method of the TV Jimin signal according to the present invention forms a transmission signal compatible with the NTSC signal for the high frequency component region of the luminance signal by frequency shifting multiple carrier waves. , N
It transmits a wideband video signal via an NTSC transmission line while maintaining compatibility with TSC signals.

The encoder according to the present invention includes a bandpass means for complementary extracting high frequency components of a wideband luminance signal to be transmitted, a sine wave generating means for frequency interleaving the extracted components, and a motion component of the wideband luminance signal. and a modulation circuit for the color difference signal to be transmitted.
Forms a signal compatible with the TSC signal.

The decoder according to the present invention forms a transmission signal compatible with the NTSfl: signal for the high-frequency component region of the luminance signal by frequency shifting multiple carrier waves, and maintains compatibility with the NTSC signal while maintaining compatibility with the NTSC transmission channel. In a decoder that manually operates a video signal according to a transmission system that transmits a wideband video signal via a video signal, a wideband luminance signal and a color difference signal are demodulated by control in response to a motion detection signal.

[Function] The present invention forms a transmission signal compatible with an NTSC signal for the high-frequency component region of a luminance signal by frequency shifting multiple carrier waves, and thereby transmits an NTSC signal through a conventional NTSC transmission line. This makes it possible to transmit wideband video signals while maintaining compatibility with

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 each show an embodiment of an encoder and a decoder using a transmission system compatible with the NTSC system.

First, the encoder shown in FIG. 1 will be explained.

The broadband luminance signal is input to a low-pass filter F (1) 2 and band-limited to the spectrum shown in FIG. 4(a). This signal is band-limited to 3.88 MHz by the C+-bass filter F(2)3, and becomes a baseband signal for the moving image area and the still image area.

The signal at point A, which is the difference between the input and output of the low-pass filter F(2)3, is input to the low-pass filter F(3)4, and is kneaded to a high frequency component of 3.86MHz, 5.79M!
The Iz band signal is extracted and the sine wave signal f1 is modulated, where tl-(ts/4)÷7.5Hz
...(1) fs-198n x fH# 30
．． 87MHz f5 double standardization frequency f: This is the horizontal scanning frequency of NTSC No. 13.

Further, the sine wave signal f2 is modulated by the signal at point B, which is the difference between the input and output of the low-pass filter F (3) 4.

Here, f2” (fs/8)+7.5Hz
-(2). The offsets of 7.5 Hz in the sinusoidal waves f and f2 are obtained by changing the phase of sampling points at integral multiples of the horizontal scanning frequency for each frame, as shown in FIGS. 8 and 9.

After the above modulated signals f, , f2 are added, they are gain-adjusted by the coefficient transformer 14, and then filtered by a low-pass filter F (2).
f3 (modulated by the output of 3 and color difference signals I and Q)
color subcarrier) is added and output via a low-pass filter F(4)5 in the 4.2M)lzlF band.

The coefficient unit 14 described above is controlled by the signal from the motion detection circuit 1, and 0≦1−, ≦1 (3) k=
0: still image area = 1: moving image area.

FIG. 5 represents the spectrum of a frequency interleaved luminance signal. Figures 4 and 7(a),
(b) shows the characteristics of the filter used in the encoder shown in FIG. Further, FIG. 6 shows detailed contents of the frequency characteristics shown in FIG. 5. However, for ease of explanation, the sampling frequency f9 is set to fs-1920Hz.
・= It is reduced to (4). Therefore, the fourth
The bands ■ to ■ shown in the figure and Fig. 5 are the bands ■ shown in Fig. 6.
Corresponding to ~■, [Ll, [2] shown in FIG. 6 are OMHz ~ about 2MHz, and about 2MHz ~ 4.2M, respectively.
Corresponds to 1lz.

In FIG. 6, the multiplication signal of the signal in the area ■ and f is:
It is marked Q in Fig. 6(C). Also, the signal in the area of ■ and f2
The multiplied signal of is marked as . The ○ marks in FIG. 6(c) are signals in the areas ■ and ■ in FIG. 6(a), and are the outputs of the low-pass filter F(2)3 shown in FIG. 1. moreover,
The x marks represent positions where the color difference signals are frequency interleaved. As is clear from this figure, since the luminance signals (1) to (4) and the color difference signals are frequency interleaved, they can be restored by the decoder.

Next, the decoder will be explained with reference to FIG.

Sine wave signals f1 and f used for frequency interleaving
2 is a 4-frame period, so in order to demodulate it, 4 frames are required.
Frame information is required. 0 points and 0 in Figure 2
The dots are the outputs of the transversal filter of 4 frame information, and the baseband (
■, ■). The characteristics are shown in FIGS. 7(C) and (d).

Block 1 surrounded by a broken line in FIG. 2 is a circuit for demodulating high frequency components (■, ■) of the luminance signal. Also, point E shown in Fig. 2 is approximately 2M1lz to 4.2 of the decoder manual signal.
It is a MHz signal. From this, subtract the F point signal which is the color difference signal and the baseband signal (■) of the luminance signal,
Frequency-interleaved signals of ■ and ■ can be obtained (signal at point G).

And band pass filter F(8)17. F(9)1
8 and a temporal filter 19, the signals of ■ and ■ are demodulated. This temporal filter 19 is constructed as shown in FIG. 3, and its electrical characteristics are shown in FIG.
c) is the same as.

The output of the temporal filter 19 and the output of the adder 10 (H
Point signal: The added signal in FIG. 7(e) becomes the signal shown in FIG. 4(a). However, since demodulation is possible only in the still image area, the signal in the video area and the coefficient multiplier 14.25
The output luminance signal is weighted and averaged.

A block 2 surrounded by a broken line in FIG. 2 demodulates a color difference signal in a moving image area using intra-field information, and this signal is used in a subtracter 8. The brightness signal of the moving image area is demodulated using the adder 10.

The motion detection circuit 1 is a well-known technique (for example, Japanese Patent Application Laid-Open No. 58-205377: adaptive spatio-temporal filter by the present applicant), so a description thereof will be omitted.

In addition, in the embodiments described so far, the sampling frequency is set to 1.
Although the frequency is 980X fH, it is not limited to this frequency.

[Effects of the Invention] As described above, according to the present invention, it is possible to significantly (approximately double) increase the high frequency information of the luminance signal while maintaining compatibility with the NTSC signal.

In this way, the drawback that the horizontal high frequency information is lower than the vertical information in the NTSC signal conventionally used for broadcasting etc. can be removed, and it can be applied to the transmission of high resolution signals such as high vision and EDTV.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an encoder to which the present invention is applied, FIG. 2 is a block diagram showing an embodiment of a decoder to which the present invention is applied, FIG. 3 is a configuration diagram of a temporal filter, and FIG. The figure shows the filter characteristics and signal spectrum used in the encoder shown in Figure 1, Figure 5 is a diagram explaining the frequency interleaving of the high frequency component of the luminance signal, and Figure 6 corresponds to Figure 5. FIG. 7 is a diagram showing the details of the spectrum; FIG. 7 is a diagram showing the characteristics of each point of the encoder and decoder according to this embodiment; FIGS. 8 and 9 are diagrams showing examples of carrier waves. DESCRIPTION OF SYMBOLS 1... Motion detection circuit, 2-7... Filter, 8... Subtractor, 9... Multiplier, lO... Adder, 11.12.13... Sine wave signal source, 14...Coefficient unit.

Claims (1)

[Claims] 1) By frequency shifting multiple carrier waves, a transmission signal compatible with an NTSC signal is formed for the high frequency component region of the luminance signal, and while maintaining compatibility with the NTSC signal, the transmission signal is
A television signal transmission method characterized by transmitting a wideband video signal via a transmission path. 2) Band-pass means for complementary extraction of high-frequency components of a wideband luminance signal to be transmitted, sine wave generation means for frequency interleafing the extracted components, and motion for detecting motion components of the wideband luminance signal. An encoder comprising a detection means and a modulation circuit for a color difference signal to be transmitted, and forming a signal compatible with an NTSC signal. 3) By frequency shifting multiple carrier waves, a transmission signal compatible with NTSC signals is formed for the high frequency component region of the luminance signal, and while maintaining compatibility with NTSC signals, NTSC
A decoder that receives a video signal according to a transmission method that transmits a wideband video signal via a transmission path, and is characterized in that the decoder demodulates a wideband luminance signal and a color difference signal by control in response to a motion detection signal.